In cooperation with Dr. G.Z. Williams and staff of the Health Research Institute (San Francisco), records of some 30 different biochemical and hematological tests performed annually over a 4-7 year period on several hundred healthy volunteers have been analyzed to test the adequacy and usefulness of 3 statistical forecasting models described in previous reports and publications. An initial report of this work is in preparation. The theory of Empirical Bayesian estimation has been explored to determine its usefulness as a way of improving estimates of individual mean values of biochemical constituents. Initially, applications to epidemiological studies have been investigated (Ref. 1). Work currently in progress tests the application of this theory to patient data from hospital laboratories. Another cooperative study examines the distribution of within-person variance in healthy volunteers and its effects on reference ranges and other medical diagnostic criteria. Finally, joint studies with cooperating pathologists have begun on the power of various statistical models and tests to detect short-term trends in biochemical quantities.